Yep, the upper arms are shorter than the lower, that is for the handling benefits.
The ball joint angle on the upper arm is supposed to be flat, thats for a reason (not saying it's perfect in our case).
Stock ride height for the S-Series trucks puts the control arms about level (hence the flat angle ball joint angle on the upper arm). What this does is when you take a corner the suspension compresses, this pulls the top of the tire in (the short upper arm) which combats the tendency of the top of the tire to push out due to body roll.
I'm sure there are more reasons too.
I am going to make the upper control arm even longer by an equated amount( geometry)
This is problematic! You can't just add length to the upper arm without adding the same (or similar) amount to the lower arm. If you don't you will never get the alignment even close. Sure, with angle on the arms you may need to add a little more depending on geometry, but it's going to be in fractions of an inch.
The other thing to remember is this is going to gain you very little height, and little travel.
The problem is the width that results from making the control arms longer. If there is say a 30 degree angle on the lower arm (thats allot), every inch of lift will equal two inches of width, on each side. So to gain 2" of lift the truck is going to be 8" wider. Lets say that 4" wider on the front track is OK, that equals 1" of lift. Now if using the stock CV
joints you can't put any more angle on them, so in effect you gain little travel, say between 2 and 3 inches.
Now you can improve on that some with better joints and what not, but thats going to give you marginal returns for the price, so lets say that will give you another 2" of travel. All in all that yields you 4-5" of additional suspension travel. Now thats decent for a pre-runner, but remember that only gains you 4-5" on a ramp too, not 8-10".
Just thoughts to think about, I still think it's an excellent project.
[size=75][b]1991 GMC Sonoma Extended Cb[/b] - 4.3L Automatic, 2" BL, 31" BFG's.
[b]1992 Chevy T-10 Reg Cab[/b] - 4.3L 5spd, 3" Bl, 31" Mud Tires. Hooker long tube headers and true duals.
[b]1999 Oldsmobile Bravada[/b] - Wifes truck, all stock.[/size]